Why and How Often to Calibrate Your Torque Wrench
Having the most accurate and reliable tools is vital to mechanical services. It is natural for torque wrenches to go out of calibration with time and consistent use. Regular calibration servicing will ensure that your tools are as accurate and effective as possible.
Why Is Torque Wrench Calibration Essential?
In most cases, it is presumed that a manual or hydraulic torque wrench will distribute the demanded torque value if set appropriately. However, torque wrenches have moving parts that will be subject to wear. They are also exposed to harsh operating conditions in the field, which increases the risk of damage. The need to control torque is a very important task to provide quality and safety. The allowable window of calibration error is 5%, and any error beyond that may seriously disturb the performance of the tool.
How Often Should You Calibrate a Torque Wrench?
First, make it a policy to calibrate torque wrenches annually or for wrenches that see heavy usage, by their 5,000th cycle -- this is from the ISO standard revision in 2003.
Not all industries give you the option to choose when torque wrenches are calibrated. Some industries have their own standards and require certification and documentation that each torque wrench is calibrated on schedule. The aviation industry is a notable example of this.
In short, calibrate each torque wrench annually or by its 5,000th cycle unless your industry requires otherwise.
Factors That Impact How Often to Calibrate a Torque Wrench
The above recommendations are for standard use. Calibrate more frequently in situations where wrenches:
- See critical and aggressive use -- above 25 percent above their maximum setting, such as in overload situations.
- Encounter environments where damage to the wrench is likely. This can be as simple as dropping the wrench or exposure to severe heat, cold or liquids, especially saltwater.
- Face high humidity.
- Receive poor care when not in use. Releasing the torque and setting the dial back to zero helps reduce the internal pressure on the wrench's components. Not setting the dial back to zero after every use is an indication that recalibration should occur more often.
As you can see, when to calibrate can vary depending on industry rules and regulations and tool use.
Where to Get a Torque Wrench Calibrated
You could calibrate torque wrenches in-house. However, by utilizing a third-party bolting service, you gain access to experts in the industry as well as top brand tools, such as the Skidmore-Wilhelm Bolt Testers, to make the process of calibrating your torque wrenches easier and get more consistent results. If you use an ISO certified calibration service, you know the company meets certain quality standards. Other advantages of third-party calibration services include:
- AISC/RCSC compliance for pre-installation verification tension testing including rotational capacity testing of structural fasteners
- Testing hex bolts, tension bolts, anchor bolts, studs and locknuts
- Direct tension bolt and washer testing
- General fastener testing
Experts in calibration services will confidently use Skidmore-Wilhelm Bolt Testers to easily determine the relationships between torque and tension. In bolting industries and businesses where torque wrenches are in demand, downtime for maintenance can be worrisome for projects with tight deadlines. Third-party bolting service providers can also perform these calibration services on site or offer tools for rent while maintenance is underway to decrease project downtime and increase efficiency.
Regular calibration will help ensure your tools are working to their full potential and will provide you peace of mind that their accuracy is on point. If you believe your industrial torque wrenches are ready for calibration or would like an expert opinion, contact Aztec Bolting Services for calibration services and 24-hour mobilization.
